arsenic

1 of 2

noun

ar·​se·​nic

ˈärs-nik,

ˈär-sə- 

1

: a solid chemical element that is used especially in wood preservatives, alloys, and semiconductors and is extremely toxic in both pure and combined forms see Chemical Elements Table

2

: a poisonous trioxide As₂O₃ or As₄O₆ of arsenic used especially as an insecticide or weed killer

called also arsenic trioxide

arsenic

2 of 2

adjective

ar·​sen·​ic är-ˈse-nik 

: of, relating to, or containing arsenic especially with a valence of five

Examples of arsenic in a Sentence

Recent Examples on the Web

Noun

Samples from multiple batches of each of the 23 different products were analyzed to assess total protein, arsenic, cadmium, lead and other elements. —New Atlas, 22 Oct. 2025

Several also contained measurable cadmium and arsenic, with cadmium levels in some cases more than twice what public health authorities consider potentially harmful daily exposure. —Deirdre Bardolf, FOXNews.com, 18 Oct. 2025

Adjective

Edwards also noted that most of the water utilities with arsenic problems served a small number of people—often 500 people or less each. —Jasmine Laws, MSNBC Newsweek, 10 Oct. 2025

The rule in question would have been expected to reduce pollution including releases of mercury and arsenic and result in fewer cancer cases as a result. —Rachel Frazin, The Hill, 29 Sep. 2025

Word History

Etymology

Noun

Middle English arsenek, arsenic "any of various compounds of arsenic, as yellow orpiment (arsenic trisulfide)," borrowed from Anglo-French & Latin; Anglo-French arsenik, arsneke, borrowed from Latin arrhenicum, arsenicon, borrowed from Greek arsenikón, arrhenikón, probably borrowed from Aramaic zarnīḵ "arsenic" or a cognate Semitic word, borrowed from an unattested form in a Middle Iranian language (whence Persian zarnī, zarnīk "orpiment, arsenic"), a derivative of the word for "gold" (as Manichaean Parthian zrn /zarn/ "gold," zrnyn /zarnēn/ "golden"), alluding to the yellow color of orpiment

Note: The Greek word is assumed to have been reshaped by folk-etymological association with arsenikós, arrhenikós "male, masculine." Aramaic zarnīḵ is attested in a papyrus text (an order to repair a boat) dated January, 411 b.c., found in elephantine, Egypt (see A. Cowley, Aramaic Papyri of the Fifth Century B.C., Oxford, 1923, pp. 88-97; B. Porten, The Elephantine Papyri in English: Three Millennia of Cross-Cultural Continuity and Change, Brill, 1996, pp. 115-22); the word is also attested in Syriac a number of centuries later. The Manichaean Parthian forms are from D. Durkin-Meisterernst, Dictionary of Manichaean Texts, vol. III, Part 1, Dictionary of Manichaean Middle Persian and Parthian, Brepols, 2004. Parthian zrn and zrnyn are continuations of an Old Iranian etymon represented by Avestan zarańiia- "gold"—see note at gold entry 1.

Adjective

from attributive or compound use of arsenic entry 1

First Known Use

Noun

1747, in the meaning defined at sense 1

Adjective

1798, in the meaning defined above

Kids Definition

arsenic

noun

ar·​se·​nic

ˈärs-nik,

-ᵊn-ik

1

: a solid poisonous element that is commonly metallic steel-gray and brittle see element

2

: a white or transparent extremely poisonous oxide of arsenic used especially in insecticides

Medical Definition

arsenic

1 of 2 noun

ar·​se·​nic ˈärs-nik, -ᵊn-ik 

1

: a trivalent and pentavalent solid poisonous element that is commonly metallic steel-gray, crystalline, and brittle

—symbol As see Chemical Elements Table

2

: arsenic trioxide

arsenic

2 of 2 adjective

ar·​sen·​ic är-ˈsen-ik 

: of, relating to, or containing arsenic especially with a valence of five